1. Field of the Invention
The present invention relates to a combinational weighing apparatus for articles and, more particularly, to the improvement in a distributing apparatus provided in the weighing apparatus and belongs to the technical field of combinational weighing apparatuses.
2. Description of the Related Art
A combinational weighing apparatus for use in weighing articles executes combinational operation based on weights of articles measured by a plurality of weighing apparatuses to select an optimum combination whose combinational weight is most approximate to a target weight within a range of a predetermined allowable error, as well as discharging and collecting articles from the weighing apparatuses selected as the optimum combination, thereby obtaining an article whose weight is most approximate to the above-described target weight. In this case, the combinational weighing apparatus is provided with an article distributing apparatus in order to distribute and supply articles fed from a supply unit to the respective weighing apparatuses.
A distributing apparatus of this kind is disclosed, for example, in Japanese Utility Model Patent Laying-Open No. 64-8638, in which a conical distributing table is provided below an article supply unit, conveyance troughs are provided below the distributing table to surround the same, and a stirring blade extending toward a peripheral edge portion of the distributing table is attached in the vicinity of an upper end of a rotation shaft extending upwardly through an apex of the distributing table so as to have a small gap between the blade and an upper surface of the distributing table, so that the rotation shaft is rotated by a drive unit disposed below the distributing table.
According to the disclosed apparatus, articles fed from the article supply unit will fall down onto the distributing table disposed below and while falling further down along the distributing table, they will be distributed by the rotation of the stirring blade and transported to the conveyance troughs.
Another apparatus of this kind is disclosed in Japanese Utility Model Patent Registration No. 2577716, which includes rotary stirring blades disposed along a slanting surface of an upper portion of a distributing table at adjustable intervals, a conical distributing element disposed above the stirring blades so as to have an adjustable gap from the stirring blades, and a drive unit rotatable integrally with the stirring blades, whereby an article supplied from above falls on the slanting surface of the conical distributing element, and includes level sensors one each at the right and left side in the vicinity of a peripheral edge of the distributing table in order to constantly monitor the volume of articles supply to the distributing table to send a signal to the drive unit, thereby rotating the conical distributing element and the stirring blades toward accumulated articles whose thickness is small.
According to the apparatus, while being distributed on the slanting surface of the conical distributing element, articles fed from above will be supplied to the distributing table by the stirring blades and a thickness of articles accumulated on the distributing table is detected by the right and left level sensors to send a signal to the conical distributing element and the drive unit of the stirring blade for rotating the same toward accumulated articles whose thickness is small, thereby supplying articles so as to have approximately even thickness.
Disclosed in Japanese Utility Model Patent Registration No. 2538633 is an article distributing apparatus including a cylindrical container whose bottom surface slants downward from the central portion to a peripheral edge portion and which is disposed below an article supply port, a conical distributing member disposed above the central portion of the container so as to be reciprocally rotatable centered around a shaft center provided vertically, and a plurality of disentangling rods extending along the bottom surface of the container with their ones of opposite ends fixed to an inner circumference of the lower end of the distributing member. In this case, the circumference of the lower end of the distributing member at the bottom surface of the cylindrical container is regarded as a reception unit for receiving articles distributed by the distributing member, and at an outer circumference of the reception unit, a plurality of article discharge ports are disposed at equal intervals on the circumference.
According to the apparatus, articles supplied from the article supply port will be distributed by the distributing member and received by the reception unit of the cylindrical container and temporarily stored. Then, the articles will be disentangled by the reciprocal rotation of the disentangling rods attached to the distributing member and then discharged to the article discharge port.
With the distributing apparatus disclosed in Japanese Utility Model Patent Laying-Open No. 64-8638, however, because of a small gap between the upper surface of the distributing table and the lower side of the stirring blades, articles are liable to be caught between the distributing table and the blades while the stirring blades rotate. Once the caught of an article occurs, further articles will be entangled in the caught article to make a mass, resulting in gradually increasing the volume of articles caught and entangled. As a result, once such entanglement as this occurs, it is impossible to distribute the articles satisfactorily.
On the other hand, in the distributing apparatus disclosed in Japanese Utility Model Patent Registration No. 2577716, as shown in FIG. 9, while there is a large gap adjustable between a lower side 101a of a stirring blade 101 and an upper surface 102a of a distributing table 102, the gap is designed to be approximately parallel. Therefore, when an article x is caught between the lower side 101a of the stirring blade 101 and the upper surface 102a of the distributing table 102, there are generated opposing forces exerted on the article x, a force xe2x80x9caxe2x80x9d directed from the lower side 101a of the stirring blade 101 toward the distributing table 102 and a force xe2x80x9cbxe2x80x9d directed from the upper surface 102a of the distributing table 102 toward the stirring blade 101, which will function as a force of catching the article x. As a result, once an article is caught, it will be hardly released, and similarly to the apparatus disclosed in Japanese Utility Model Patent Laying-Open No. 64-8638, a further article will be entangled in the caught article to result in insufficient distribution of articles.
Similarly to the distributing apparatus disclosed in Japanese Utility Model Patent Registration No. 2577716, the distributing apparatus disclosed in Japanese Utility Model Patent Registration No. 2538633 also has the problem that articles can not be satisfactorily distributed because a gap between an upper surface of the distributing table and a lower side of the disentangling rod is approximately parallel to each other.
Accordingly, it is an object of the present invention to provide a combinational weighing apparatus having a distributing apparatus capable of preventing articles from being caught in a gap between a distributing table and a stirring member to distribute articles as uniformly as possible.
According to one aspect of the present invention, the combinational weighing apparatus includes a distributing apparatus for distributing articles supplied from above, a plurality of conveyance apparatuses radially disposed below and around the distributing apparatus and a plurality of weighing apparatuses disposed below the respective conveyance apparatuses, the distributing apparatus including a conical distributing table, a stirring member having one end attached to a rotation shaft arranged at an apex portion of the distributing table and the other end extending slantwise downward to the vicinity of a peripheral edge of the distributing table, and a drive unit for rotating the rotation shaft, with a gap between a lower side of the stirring member and an upper surface of the distributing table being increased as it goes downward.
According to the present invention, the articles supplied from above fall onto the conical distributing table. At this time, rotation of the stirring member having one end attached to the rotation shaft arranged at the apex portion of the distributing table and the other end extending slantwise downward to the vicinity of the peripheral edge portion of the distributing table around the rotation shaft caused by the drive unit for rotating the rotation shaft to a predetermined direction results in distributing the articles. In this case, since the lower side of the stirring member is disposed to have a gap from the upper surface of the distributing table which is designed to become larger downwardly, when an article is caught between the lower side of the stirring member and the upper surface of the distributing table, a composite force of a force exerted from the stirring member onto the article and a force exerted from the distributing table onto the article will be a force directed slantwise downward. In other words, because a composite force works on the article which will bring the article from a place where the gap is small to a place where the same is large, even when the article is caught, it will be pushed downward, resulting in making the articles less liable to be continuously caught between the stirring member and the distributing table. Moreover, because the above-described composite force will work on an article at a time when the article comes into contact with the stirring blade rotating on the distributing table, it is less liable to be caught, which leads to reduction in the occurrence of a state where an article is caught. As a result, it is possible to minimize the occurrence of the state where articles are caught between the stirring member and the distributing table and even when it is caught, possible to release it in a short time period to enable articles to be distributed to the conveyance apparatuses as uniformly as possible.
According to another aspect of the present invention, the stirring member of the above-described invention is configured to exert a force on an article on the distributing table which makes the article directed toward a peripheral edge when rotating to come into contact with the article.
According to the present invention, when rotating to come into contact with an article on the distributing table, the stirring blade will exert a force onto the article so as to be directed toward the peripheral edge. As a result, the article will be pushed forward directly by the stirring member toward the direction in which the gap between the stirring member and the distributing table is increased, whereby the above-described functions and effects of the present invention are enhanced to further reduce the occurrence of the state where the articles are caught to enable as uniform distribution of articles to the conveyance apparatus as possible.
According to a further aspect, the distributing table of the above-described invention is characterized in being fixed to the main body of the weighing apparatus.
According to the present invention, being fixed to the main body of the weight apparatus, the distributing table will generate none of such oscillation as causing a measurement error. As a result, precision in measurement can be improved.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.